How often to replace a shaft seal?

[hd002e]

My shaft seal was installed new 4 years ago and recently developed a leak that increases with vibration. The boat bottom and shaft have a lot of growth and initially I thought the growth was throwing it off balance. But it also leaks even when the engine is not in gear. So maybe there is growth in the shaft tube?

Is this something I can resolve by getting the bottom cleaned and seal silicone lubed? Or would I need to get a replacement seal?

The seal is a volvo penta dripless that was last serviced (lubed) 2 years ago.

Is it normal to replace this seal after 4 years of usage?

[sailormed]

No, not normal when regular maintenance is carried out. My neighbour had a boat where he replaced this exact shaft seal after 18 years! The seal consists of 2 outwards bent lips, pressed on the shaft and cooled by the water pressure for the outer ones, and greased for the inner ones.

After every haulout you have to “burb” the seal = eliminate air, because no cooling of heated rubber lips.
You also have to inject a small amount of waterproof grease in the space between the 2 lip seals at least once a year. The best way to do so is to take a half drink straw and fill it with grease. Flatten the end of the straw and insert under the lip. Then press out all the grease into the space behind the inner lipseal.

Failing to do the required maintenance will lead to premature wear of the fragile lips and cause water coming in.

Volvo requirement is to replace after 5 years, but this is manufacturer recommanded interval, a “cover my ass” attitude. Just check regularly. Even if it leaks it will not be a catastrophic failure.

[deblen]

There are several Youtube videos re Volvo Penta Shaft Seal. / Len
Mine has been in service for 15+ yrs.

https://www.youtube.com/watch?v=WZbtsMlGj2o

[9intheafternoon]

I have the same seals on my boat, installed new 3 years ago. I agree with Sailormed, with perhaps the addition that I was advised by Volvo to bleed it regularly. Like before each use, if it had sat for a few weeks. Just squeze it hard in the middle, and a bit of water should trickle in. And make sure the grease gets all the way in there. Volvo gave 5 years warranty on my seals, but only if serviced yearly by Volvo! If leaking , I´d replace it! They´re not that expensive, and can be replaced without hauling the boat (by experienced tecnician and a diver!) If you´re confident doing this yourself, even better!

[sailormed]

Before replacing or firs install check the surface of the shaft where it is in contact with the seal. The slightest nick or irregularity will kill the soft rubber sealing lips in no-time!

[GordMay]

See also ➥ https://www.cruisersforum.com/forums...box-41931.html

[slug]

Originally Posted by hd002e

My shaft seal was installed new 4 years ago and recently developed a leak that increases with vibration. The boat bottom and shaft have a lot of growth and initially I thought the growth was throwing it off balance. But it also leaks even when the engine is not in gear. So maybe there is growth in the shaft tube?

Is this something I can resolve by getting the bottom cleaned and seal silicone lubed? Or would I need to get a replacement seal?

The seal is a volvo penta dripless that was last serviced (lubed) 2 years ago.

Is it normal to replace this seal after 4 years of usage?
Attachment 213439

The shaft must be perfectly smooth , no wear grooves or the seals wear

Also the bearing seal is water lubricated

When you haul out, the stuffing box drains dry
When you launch water can’t flood the bearing .... an air pocket forms

If the shaft turns the lubricated bearing wears fast

To get rid of the bubble the stuffing bow must be bled

[svHyLyte]

We have the same seal on a 30mm drive shaft. The Volvo literature indicates the life-span as about 5 years in "normal" use although normal isn't defined. The literature also explains that the seal should be lubricated with a water-proof grease, preferably teflon, at least annually (one fills a plastic straw, flattened on one end with grease, squeezes the end of the seal enough to get it to raise enough to get the flattened end of the straw under the seal and then, patiently, "milks" the grease through the straw and into the seal). We routinely motor for an hour or two at least once a week departing and returning to our marina and, following the foregoing maintenance conventions, normally get about 7 years of service out of a seal.

Note that, in extremis, one can "reinforce" the seal to minimize leakage by tightening a wide plastic zip-tie around the inboard end although this repair will not last very long. I would only employ the method if the yacht were stationary and then until I could get her to a haul-out lift. Replacement of the seal isn't difficult, but awkward (and, of course, the seals are no longer inexpensive!).


FWIW...

[rjash6666]

I have had my Gibsea33 for nearly 19 years and about 10 years ago I replaced the shaft seal because someone sid that I should. Still no sign of a leak on the replacement. Am I tempting providence?

[StoneCrab]

If you have vibration, I'd look at the shaft bearings.
I've replaced my Cutlass bearing a few times.

[skalashn]

Shaft vibration will cause the Volvo seal to wear prematurely and leak. Mine did. Replaced with PSS, not a drop of water in 5 years, maintenance free.

[StoneCrab]

Originally Posted by skalashn

Shaft vibration will cause the Volvo seal to wear prematurely and leak. Mine did. Replaced with PSS, not a drop of water in 5 years, maintenance free.

What is PSS?

[skalashn]

https://www.shaftseal.com/

[barnakiel]

This is the Volvo one?


Volvo gives exactly the replacement interval on their site. Why confirming this at the forum? You do not trust Volvo?


If I remember well, about 10 years of life, unless it is worn too much and drips badly.


Turning it some tends to stop the drip if drip is the problem.


Clean it and grease it annually.



Cheers,
b.

[barnakiel]

2nd part:


IT WILL drip if worn badly (e.g. from sand or silt in your sailing area),



OR


if the engine is off line, or has recently moved (e.g. a bad engine mount).


Try turning it as I mentioned earlier). Ease, turn, fix, start engine, test. Leaking? Then turn a bit more. Very often you can find a zero leak point again like this. Except if the shaft / engine are way off. Or when the seal is worn off (as said, mud,silt,sand or fine hard debris in water).


Cheers,
b.